Here's the classic egg in the bottle science experiment that is more than a hundred years old and is guaranteed to entertain. We will learn about air pressure while conducting it. The object is get the hard boiled egg into and out of the bottle without breaking the egg.

1) Hard boil some eggs. Let them cool in a bowl of cool water for at least 10 minutes after hard boiling.

2) Carefully remove the shells and put them back in the cool water bowl. Let your unshelled hard boiled eggs sit in the water bowl until you lift out to put onto the bottle top in step 7 below.

3) Set a hard boiled egg on top of the glass jar and show everyone it will not go down into the container on it's own without force. Then remove and put back into the water.

4) Dip you finger in the water and get a little moisture on it. Rub that on the rim of the glass to give it a little lubrication.

5) Rip a small piece of paper off.

6) Light the paper on fire with the lighter. Let it get going pretty good, then quickly put the ignited paper into the glass bottle.

7) Now be fast with this part. After you put the lit paper into the glass bottle, gently place the egg on top of the bottle. Be quick because the fire will go out fast.

8) Sit back and watch the egg get sucked down into the bottle. Listen for the cool sucking sound as it goes inside!

9) Now amaze your friends by getting the egg back out of the bottle without breaking it. To do this, rub some more water with your finger around the edge of the bottle opening (inside). Turn the bottle upside down and let the egg fall into the opening of the bottle mouth. Notice it does not want to come out. Now place your mouth over the mouth of the bottle while holding it upside down. Blow really hard. No really hard. You want to force some air behind the egg and into the back of the bottle. Remove your mouth and the egg will start to come back out. It most likely came about 1/2 to 3/4 back out. Now gently pull it the rest of the way. The secret is keep the bottle upside down while blowing and the keep the egg in the bottle neck while blowing.

The Science Behind The Egg In A Bottle ExperimentWhen we ignite the piece of paper it heats the molecules of air inside the bottle. This makes the molecules expand and move away from each other. They go up and out of the bottle with the heat from the fire. Once the fire is extinguished the air cools down, but the egg on top of the bottle prevents new air from outside from entering the bottle. The air pressure inside the bottle is now lower since new air from outside has been prevented from moving inside (new air can't fill the empty space in the bottle). This means the air pressure outside is greater than inside the bottle. As a result the greater air pressure outside pushes the egg down into the lower pressure bottle. Pretty cool! Now go an do the egg in a bottle experiment with some friends!